The invention relates to an arrangement for joining two sectional parts, in particular frame parts of metal windows, with at least one connecting strip of plastic or similar heat-insulating material which comprises strip type catch lugs which are received in a U-piece of a sectional part and are fixed by lateral projections engaging in corresponding undercuts of the U-pieces.
In a known insulating section (Swiss Pat. No. 411,290), the catch lugs comprise a unilateral wedge-shaped projection whose length corresponds to the hollow-form depth of the U-pieces receiving them. Exact dimensions of the catch lugs are therefore a prerequisite for secure locking. Besides the catch lugs, the connecting strips in the known arrangement comprise abutment faces which determine the distance of the connected sectional parts. From this, too, special requirements exist for accurately sizing the connecting strips; being that plastic parts are involved, it is difficult to maintain narrow manufacturing tolerances.
In another known insulating section (German Utility Model No. 7522 009) the plastic connecting strips do not have the mentioned abutment faces; but the catch lugs extend here, too, over the entire depth of the cavity of the U-pieces. The catch lugs are divided the cut into two lobes with lateral cuts which snap into corresponding projections of the U-pieces receiving them. As the expansion effect of the catch lugs is slight, rods are subsequently driven into the cuts to ensure a safe hold of the connecting strips.
In contradistinction, it is the object of the present invention to improve the known arrangements for the joining of two sectional parts in twofold respect; for one thing, the requirements for accuracy of dimensions are to be substantially reduced and for another, a secure snapping in and firm hold of the catch lugs in the interior of the U-pieces receiving them are to be achieved.